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Posts Tagged ‘cosmology’

First Direct Evidence Of Inflation And Primordial Gravitational Waves


Credit: The BICEP2 Collaboration

Credit: The BICEP2 Collaboration

Astronomers announced today that they have acquired the first direct evidence that gravitational waves rippled through our infant universe during an explosive period of growth called inflation. This is the strongest confirmation yet of cosmic inflation theories, which say the universe expanded by 100 trillion trillion times in less than the blink of an eye.

“The implications for this detection stagger the mind,” says Jamie Bock, professor of physics at Caltech, laboratory senior research scientist at the Jet Propulsion Laboratory (JPL) and project co-leader. “We are measuring a signal that comes from the dawn of time.”

Our universe burst into existence in an event known as the Big Bang 13.8 billion years ago. Fractions of a second later, space itself ripped apart, expanding exponentially in an episode known as inflation. Telltale signs of this early chapter in our universe’s history are imprinted in the skies in a relic glow called the cosmic microwave background. Tiny fluctuations in this afterglow provide clues to conditions in the early universe.

Small, quantum fluctuations were amplified to enormous sizes by the inflationary expansion of the universe. This process created density waves that make small differences in temperature across the sky where the universe was denser, eventually condensing into galaxies and clusters of galaxies. But as theorized, inflation should also produce gravitational waves, ripples in space-time propagating throughout the universe. Observations from the BICEP2 telescope at the South Pole now demonstrate that gravitational waves were created in abundance during the early inflation of the universe.

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Four New Galaxy Clusters Take Researchers Further Back In Time

February 13, 2014 Leave a comment

pia17934-640_smFour unknown galaxy clusters each potentially containing thousands of individual galaxies have been discovered some 10 billion light years from Earth.

An international team of astronomers, led by Imperial College London, used a new way of combining data from the two European Space Agency satellites, Planck and Herschel, to identify more distant galaxy clusters than has previously been possible. The researchers believe up to 2000 further clusters could be identified using this technique, helping to build a more detailed timeline of how clusters are formed.

Galaxy clusters are the most massive objects in the universe, containing hundreds to thousands of galaxies, bound together by gravity. While astronomers have identified many nearby clusters, they need to go further back in time to understand how these structures are formed. This means finding clusters at greater distances from the Earth.

The light from the most distant of the four new clusters identified by the team has taken over 10 billion years to reach us. This means the researchers are seeing what the cluster looked like when the universe was just three billion years old.

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Massive Neutrinos Solve A Cosmological Conundrum

February 10, 2014 Leave a comment

Galaxy2-Cropped-445x124_smScientists have solved a major problem with the current standard model of cosmology by combining results from the Planck spacecraft and measurements of gravitational lensing to deduce the mass of ghostly sub-atomic particles called neutrinos.

The team, from the universities of Nottingham and Manchester, used observations of the Big Bang and the curvature of space-time to accurately measure the mass of these elementary particles for the first time.

The recent Planck spacecraft observations of the Cosmic Microwave Background (CMB) – the fading glow of the Big Bang – highlighted a discrepancy between these cosmological results and the predictions from other types of observations.

The CMB is the oldest light in the Universe, and its study has allowed scientists to accurately measure cosmological parameters, such as the amount of matter in the Universe and its age. But an inconsistency arises when large-scale structures of the Universe, such as the distribution of galaxies, are observed.

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Hubble Helps Solve Mystery Of Ultra-Compact, Burned-Out Galaxies

January 29, 2014 Leave a comment

A certain class of massive galaxies in the early universe lived fast and died young. By “died” astronomers mean that the galaxies had completed building stars just 3 billion years after the big bang. By contrast, our 12-billion-year-old Milky Way galaxy continues making stars today. When star formation stops, the aging stellar population looks redder in the star-forming galaxies that are more bluish. The nickname for the essentially “burned-out” galaxies is “red and dead.”

By combining the power of Hubble with infrared space-based telescopes and ground-based telescopes, astronomers have now solved a decade-long mystery as to how compact elliptical-shaped galaxies existed when the universe was so young. These “red and dead” galaxies have now been linked directly to an earlier population of dusty starburst galaxies. These objects voraciously used up available gas for star formation very quickly. Then they grew slowly through merging as the star formation in them was quenched, and they eventually became giant elliptical galaxies.

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UCSC Scientists Capture First Cosmic Web Filaments At Keck Observator

January 21, 2014 Leave a comment

CREDIT: S. CANTALUPO (UCSC); JOEL PRIMACK (UCSC); ANATOLY KLYPIN (NMSU)

CREDIT: S. CANTALUPO (UCSC); JOEL PRIMACK (UCSC); ANATOLY KLYPIN (NMSU)

Astronomers have discovered a distant quasar illuminating a vast nebula of diffuse gas, revealing for the first time part of the network of filaments thought to connect galaxies in a cosmic web. Researchers at the University of California, Santa Cruz, led the study, published January 19 in the journal, Nature.

Using the 10-meter Keck I telescope at the W. M. Keck Observatory in Hawaii, the researchers detected a very large, luminous nebula of gas extending about 2 million light-years across intergalactic space.

“This is a very exceptional object: it’s huge, at least twice as large as any nebula detected before, and it extends well beyond the galactic environment of the quasar,” said Sebastiano Cantalupo, first author of the paper and a postdoctoral fellow at UC Santa Cruz.

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Hubble And Galaxy Zoo Find Bars And Baby Galaxies Don’t Mix

January 17, 2014 Leave a comment

Barred spiral galaxy NGC 1300. Credit: HST / NASA / ESA

Barred spiral galaxy NGC 1300. Credit: HST / NASA / ESA

Harnessing the power of both the Hubble Space Telescope and the citizen science project Galaxy Zoo, scientists from the University of Portsmouth have found that bar-shaped features in spiral galaxies accelerate the galaxy aging process.

The astronomers found that the fraction of spiral galaxies with bar features has doubled in the last eight billion years – the latter half of the history of the universe. The scientists publish their results, the first from the Galaxy Zoo: Hubble project, in the journal Monthly Notices of the Royal Astronomical Society.

University of Portsmouth postgraduate researcher Tom Melvin led the new study as part of his thesis work. He and the rest of the Galaxy Zoo science team used classifications provided by citizen scientists to select spiral galaxies across the Universe for the study. Light from the furthest galaxies has taken eight billion years to reach us, so we see them as they appeared eight billion years ago or when the cosmos was a little over half its present age. This allows astronomers to study how the characteristics of galaxies change over this time.

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First Detailed Look At A Normal Galaxy In The Very Early Universe

January 10, 2014 Leave a comment

University of Hawaii at Manoa astronomer Regina Jorgenson has obtained the first image that shows the structure of a normal galaxy in the early universe as captured by the W. M. Keck Observatory. The results were presented at the winter American Astronomical Society meeting being held this week near Washington, DC.

The galaxy, called DLA2222-0946, is so faint that it is virtually invisible at all but a few specific wavelengths. It is a member of a class of galaxies thought to be the progenitors of spiral galaxies like our own Milky Way.

These galaxies are known to contain most of the neutral gas that is the fuel for star formation, so they are an important tool for understanding star and galaxy formation and evolution. Discovered and classified over 30 years ago, they have been notoriously difficult to see directly.

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One-Percent Measure Of The Universe Constrains Dark Energy

January 10, 2014 Leave a comment

At the January AAS meeting, researchers from the Baryon Oscillation Spectroscopic Survey (BOSS) announced that they have measured the distance to galaxies more than six billion light years away to an accuracy of one percent. Together with information on the rate at which the Universe was expanding, these measurements allow the scientists at the Max Planck Institute for Extraterrestrial Physics to place powerful constraints on the properties of the mysterious Dark Energy. This component is thought to be responsible for the current accelerated expansion of the Universe.

The new distance measurements were presented at the meeting of the American Astronomical Society by Harvard University astronomer Daniel Eisenstein, the director of SDSS-III. They are detailed in a series of articles submitted by the BOSS collaboration last month and available online. “Determining distance is a fundamental challenge of observational astronomy,” said Eisenstein. “You see something in the sky — how far away is it?”

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Liftoff For Europe’s Billion-Star Surveyor

December 19, 2013 1 comment

Copyright ESA–S. Corvaja, 2013

Copyright ESA–S. Corvaja, 2013

19 December 2013 ESA PR 44-2013: ESA’s Gaia mission blasted off this morning on a Soyuz rocket from Europe’s Spaceport in Kourou, French Guiana, on its exciting mission to study a billion suns.

Gaia is destined to create the most accurate map yet of the Milky Way. By making accurate measurements of the positions and motions of 1% of the total population of roughly 100 billion stars, it will answer questions about the origin and evolution of our home Galaxy.

The Soyuz launcher, operated by Arianespace, lifted off at 09:12 GMT (10:12 CET). About ten minutes later, after separation of the first three stages, the Fregat upper stage ignited, delivering Gaia into a temporary parking orbit at an altitude of 175 km.

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ESA’s Billion Star Surveyor: UCL’s Contribution

December 18, 2013 Leave a comment

On Thursday 19 December at 09:12 GMT, a satellite designed to unlock the secrets of the birth and evolution of the Milky Way Galaxy will be launched by the European Space Agency.

UCL’s Mullard Space Science Laboratory has played a major part in the satellite – named Gaia – for 12 years, developing the instrument that will measure the speed, temperature, size and age of over a billion stars in our galaxy.

Gaia’s mission is to slowly scan the sky, rotating every six hours, and survey the whole sky some hundred times in its six year mission. It has two extraordinarily stable telescopes, each focussing on the same huge array of 106 electronic detectors, the biggest ever either launched into orbit or on any Earth-based telescope.

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